Embodiments described herein relate generally to the parenteral procurement of bodily-fluid samples, and more particularly to devices and methods for parenterally-procuring bodily-fluid samples with reduced contamination from microbes or other contaminants exterior to the bodily-fluid source, such as dermally-residing microbes.
Health care practitioners routinely perform various types of microbial tests on patients using parenterally-obtained bodily-fluids. In some instances, patient samples (e.g., bodily-fluids) are tested for the presence of one or more potentially undesirable microbes, such as bacteria, fungi, or yeast (e.g., Candida). Microbial testing may include incubating patient samples in one or more sterile vessels containing culture media that is conducive to microbial growth, real-time diagnostics, and/or molecular PCR-based approaches. Generally, when such microbes are present in the patient sample, the microbes flourish over time in the culture medium. After a variable amount of time (e.g., a few hours to several days), organism growth can be detected by automated, continuous monitoring. Such automated monitoring can detect carbon dioxide produced by organism growth. The culture medium can then be tested for the presence of the microbes. The presence of microbes in the culture medium suggests the presence of the same microbes in the patient sample which, in turn, suggests the presence of the same microbes in the bodily-fluid of the patient from which the sample was obtained. Accordingly, when microbes are determined to be present in the culture medium, the patient may be prescribed one or more antibiotics or other treatments specifically designed to treat or otherwise remove the undesired microbes from the patient.
Patient samples, however, can become contaminated during procurement and/or can be otherwise susceptible to false positive results. One way in which contamination of a patient sample may occur is by the transfer of microbes from a bodily surface (e.g., dermally-residing microbes) dislodged during needle insertion into a patient and subsequently transferred to a culture medium with the patient sample. The bodily surface and/or other undesirable external microbes may be dislodged either directly or via dislodged tissue fragments, hair follicles, sweat glands and other skin adnexal structures. Another possible source of contamination is from the person drawing the patient sample. For example, a doctor, phlebotomist, nurse, etc. can transfer contaminants from their body (e.g., finger, arms, etc.) to the patient sample and/or to the equipment containing the patient sample. Expanding further, equipment and/or devices used during a patient sample procurement process (e.g., patient to needle, needle/tubing to sample vessels, etc.) often include multiple fluidic interfaces that can each introduce points of potential contamination. The use of such equipment and/or devices typically includes manual intervention to connect and/or fluidically couple various interfaces. Since these interfaces are not preassembled and sterilized as a single fluidically coupled system, external contaminants can be introduced to the patient sample via the user (e.g., doctor, phlebotomist, etc.) and/or other sources (e.g. ambient air, contaminants on surfaces of tables and counters in patient room, microbes transferred from linens or clothing, etc.). In some instances, such contaminants may thrive in a culture medium and eventually yield a positive microbial test result, thereby falsely indicating the presence of such microbes in vivo.
In some instances, false positive results and/or false negative results can be attributed to a specific volume of the patient sample. For example, overfilling of volume-sensitive blood culture bottles can lead to false positive results as noted in the instructions for use and/or warning labeling from manufacturers of such culture bottles, as well as associated automated continuous monitoring microbial detection systems. On the other hand, as another example, insufficient patient sample volume within a culture medium can result in false negative results. By way of example, in a study performed by the Mayo Clinic entitled, “Optimized Pathogen Detection with 30-Compared to 20-Milliliter Blood Culture Draws,” published in the December 2011 issue of Journal of Clinical Microbiology, a patient sample volume of 20 milliliters (mL) can result in detection of about 80% of bacteremias present in a patient sample, a patient sample volume of 40 mL can result in detection of about 88% of the bacteremias, and a patient sample volume of 60 mL can result in detection of about 99% of the bacteremias.
Such inaccurate results as a result of contamination, insufficient patient sample volume, and/or the like are a concern when attempting to diagnose or treat a suspected illness or condition. For example, false negative results from microbial tests may result in a misdiagnosis and/or delayed treatment of a patient illness which, in some cases, could result in the death of the patient. Conversely, false positive results from microbial tests may result in the patient being unnecessarily subjected to one or more anti-microbial therapies, which may cause serious side effects to the patient including, for example, death, as well as produce an unnecessary burden and expense to the health care system due to extended length of patient stay and/or other complications associated with erroneous treatments. Additionally, the use of diagnostic imaging equipment attributable to these false positive results is also a concern from both a cost as well as patient safety perspective as unnecessary exposure to concentrated radiation associated with a variety of imaging procedures (e.g., CT scans) has many known adverse impacts on long-term patient health.
As such, a need exists for sterile “all-in-one” bodily-fluid collection devices and methods that reduce microbial contamination in bodily-fluid test samples by, for example, minimizing exposure of the patient sample and/or fluidic interfaces to ambient non-sterile conditions and/or other sources of external contamination. Additionally, a need exists for such bodily-fluid collection devices to include a means for accurately metering, measuring, and/or otherwise assessing and confirming a volume of bodily-fluid transferred from a patient to a sample reservoir or culture medium that can be visually, tactically, or otherwise communicated to a healthcare practitioner procuring the patient sample in substantially real-time (e.g. at the patient bedside).